Water: Health Benefits, Safety and More!

Everything you need to know about water: tastier tap water, easy ways to protect our most precious resource and more.

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A cool rain shower. An afternoon of gardening. Homemade iced tea and the clink of ice cubes in a glass. With spring, our thoughts turn to water, that essential element of life which makes up 70 percent of the planet’s surface and 60 percent of your body. What’s not to enjoy? Water has zero calories, helps keep us hydrated and healthy, and is more important for survival than food is.

But lately, such happy thoughts have become clouded with confusion. Polluted drinking water is Americans’ number-one environmental concern, according to a Gallup survey, with half of those polled saying they “worry a great deal” about the issue. Bottled water could be the answer—if it weren’t costly and cruel to the planet. Which leaves us wondering exactly how we’re supposed to get our eight glasses a day. (Wait, what do you mean that’s a myth?) To quench your thirst for knowledge, tap into our A-to-Z guide to H₂O. These pages reveal everything you need to know to get safer, tastier water from your faucet, plus lots of easy ways to protect the most precious resource on this green (and blue) earth.

Why water? Because it can…

Perk you up.Dehydration can cause you to feel fatigued and sluggish, and it forces your brain to work harder than it would otherwise to perform the same tasks, explains Matthew J. Kempton, Ph.D., a postdoctoral researcher at King’s College London. “Cells must have water to function,” Kempton says. “If they can’t get enough water, they can’t do their jobs properly.”

Strengthen your skeleton. Not a dairy devotee? Drinking mineral water may help up your calcium intake and prevent bone loss, says Joseph Lane, M.D., who studies bone health at the Hospital for Special Surgery in New York City. Filtered and spring waters have minimal amounts of the bone builder, but Dr. Lane’s research shows mineral water contains an average of 208 milligrams of calcium per liter. That’s about one fifth of the recommended daily intake for women younger than 50, who should get 1,000 mg per day.

Defeat weight creep. Drinking water cooled to 37.4 degrees may lead to a slight increase in calorie expenditure for an hour after you quaff it, a study in the Journal of Clinical Endocrinology & Metabolism finds. (The cool liquid forces your body to work to maintain its internal temperature.) And a glass before a meal—chilled or not—may curb your appetite slightly, helping cut calories.

And maybe protect your heart. When a National Institutes of Health–funded study tracked 34,000 people for 14 years, it found that men who downed five to six glasses of water a day were nearly 70 percent less likely to die of a heart attack. The correlation wasn’t as strong in women, but “it’s a very intriguing finding,” says study director Gary Fraser, M.D., a cardiologist at Loma Linda University Medical Center in California. “We are now following 96,000 men and women in another study and will see if the preliminary results hold.”

How to hydrate (beer included)

“Staying hydrated is essential for normal body function,” says Selina Shah, M.D., a physician at the Center for Sports Medicine in San Francisco. But exactly how much water we should drink is a matter of debate. Part of the problem with the famous rule of eight 8-ounce glasses a day is that it fails to account for the water we get naturally through our diet, says Heinz Valtin, M.D., a kidney specialist who debunked the trope in a study at Dartmouth Medical School. “Fruit and vegetables, for instance, are 80 to 90 percent water,” Dr. Valtin notes.

Thus, consuming 2 quarts of fluid (yep, that’s 8 ounces times eight) remains a good goal, “but soups, fruit and vegetables, tea and coffee—even the caffeinated kind—all count toward this total,” says American Dietetic Association spokeswoman Christine Gerbstadt, M.D., a physician and registered dietitian in Sarasota, Florida. Dr. Valtin argues that in moderation, even alcoholic drinks such as beer can count toward our daily healthy fluid intake. (We like Dr. Valtin.) “In large doses, caffeine and alcohol can be diuretics but not in the concentrations of a cup or two of coffee or one cocktail,” he says.

In general, pale urine means you’re hydrated. If it’s dark or there’s not a lot of it, start guzzling. Aim for even more fluids if you’re active, if it’s hot or both. “Women should drink an additional 8 to 16 ounces for every half hour they sweat through activity and heat,” Dr. Gerbstadt says. Electrolyte-infused H₂O can help replace the potassium, calcium and magnesium lost through sweat after an hour of intense exercise, Dr. Shah says, but it isn’t any more hydrating than what comes out of the tap.

Is my tap water clean?

The short answer: yes. But it could and should be cleaner, says Renee Sharp, a senior scientist at the Environmental Working Group, a research nonprofit in Washington, D.C. In 2009, Sharp helped compile a report that analyzed more than 20 million drinking-water tests done by water suppliers that service 256 million people nationwide. That review uncovered a total of 316 contaminants, including pesticides; bacteria; naturally occurring pollutants, like lead and arsenic; chemicals such as trihalomethanes—by-products created when utilities treat polluted water with disinfectants; and MTBE, a gasoline additive.

Government budget cuts have been shortchanging our sewers, treatment plants and inspection programs, Sharp says. “We don’t want to scare people—tap water, especially if you use a filter, is fine to drink. Drinking water in the United States is safer than it is in most of the world. But there’s always room for improvement,” she adds.

The best way to know what’s coming out of your faucet is to ask for a water-quality report from the company that sends you your bill, says David R. Wunsch, Ph.D., a founding member of the Subcommittee on Ground Water at the U.S. Department of the Interior. “People know more about their furnaces and electric systems, but water is what we put into our bodies.” Even if your tap gets the all-clear, a water filter (find one below) is a smart precaution. Look for NSF on the label, which means testing confirms the filter reduces threats to your health.

Flustered by filters? Chart your choices here

For most waterThe solution: In the majority of homes, a carbon filter system is all that’s needed. Depending on your preference, you can get a carbon-filter pitcher, a faucet attachment or an under-the-sink unit.

How it works: Naturally absorbent carbon particles, which are activated with a positive charge, attract negatively charged impurities, reducing the amount of pesticides, bacteria and chemicals in your water.

For high-risk waterThe solution: If your water tests positive for contaminants that carbon doesn’t weed out, such as lead and arsenic, invest in a reverse-osmosis filter, which does more heavy-duty filtering.

How it works: Installed under the sink, these units force water through a semipermeable membrane in order to capture contaminants, including perchlorate, a component of rocket fuel found in water near some military bases.

For hard waterThe solution: Consider a softener or a shower filter if you have water that’s heavy on calcium and magnesium. Water that’s hard (but not harmful) may have a distinct taste, and in the shower, the minerals can clog pores and coat your hair, leaving it a frizzy mess.

How it works: Softeners remove minerals from water by way of an ion exchange, swapping sodium ions for calcium and magnesium. Shower filters contain particles that absorb chlorine.

Try: The AquaKinetic Series Water Softener (price upon request) from Kinetico or the Aquasana Shower Filter ($85)

No trash left behind

Ever unthinkingly throw your garbage into a storm drain on the street? Think on this: Your litter may have gone to a nearby lake or river, perhaps the one that is the source of your water. You could be polluting in less obvious ways, too.

Bathroom trash The only things that should ever swirl down your drain are numbers one and two, plus toilet paper. Cotton balls, tampons, condoms—they all travel through the sewers and could end up in the water we drink and fish from. The more debris in the water, the more chemicals may be needed to clean it.

Gizmos “Anything that contains a circuit board—cell phones, iPods, computers—is full of toxic chemicals,” says Barbara Kyle, national coordinator of the Electronic TakeBack Coalition. Even tiny items add up in a landfill, where these chemicals can seep into our groundwater. Find an e-cycler at ElectronicsTakeBack.com.

Motor oil Oil and antifreeze are major contaminants of waterways. Have your car checked according to the manufacturer’s maintenance schedule, repair leaks immediately, and get rid of oil at designated centers only. Locate one at Earth911.org.

Germ fighters Skip the antibacterial soap; it works no better than regular suds. Most brands contain triclosan, a chemical known to alter hormone regulation; we wash it down the drain, where it may end up in our drinking water.

Rx drugs Eighty percent of water sampled in a U.S. Geological Survey study carried traces of pharmaceuticals, in part because Americans flush unused pills. On April 30, hand over extra meds to the Drug Enforcement Administration during National Prescription Drug Take-Back Day. Check DEA.gov for a site near you. No one wants to drink your drugs.

Go cold

Use the hot faucet for dishes, but for drinking and cooking, keep it cool. Hot water dissolves contaminants more quickly than cold. Old or corroded pipes may contain lead that can leach into your water as the hot stuff makes its way to your tap.

Bottle backlash

Has plastic lost its luster? Nearly 25 percent of Americans switched from bottled water to tap in the past year, according to a Harris poll. Numerous studies have uncovered no evidence that bottled is any purer or safer than tap is, and the government inspects it far less often. Cities including Seattle and San Francisco have passed laws banning the use of municipal funds to pay for the bottled stuff. “Bottled water was shrouded in a myth of purity,” says Emily Wurth, director of water policy for Food & Water Watch, a group that runs the anti–bottled water campaign Take Back the Tap.

Add to these problems clogged landfills and the extra expense (bottled water costs up to $8.26 per gallon compared with $0.002 per gallon for tap) and the best advice is to make friends with your faucet. Use an aluminum bottle to carry tap water on the go, and consider bottled water a splurge for convenience, says John R. Bucher, Ph.D., associate director of the National Toxicology Program at the National Institute of Environmental Health Sciences in Research Triangle Park, North Carolina. And know that not all bottles are born equal. Here’s a look behind the labels.

Purified water is filtered tap water. Many companies resell municipal water from the cities nearest their regional bottlers. They treat it with processes such as reverse osmosis to remove impurities and reduce the chlorine taste.

Springwater, such as Evian and Poland Spring, comes from natural underground aquifers that bubble to the surface of the earth. Constantly moving springwater is self-sanitizing and often contains more minerals, including calcium, than purified water. Springs also regenerate, depleting less water from the earth. (The bottles are still shipped thousands of miles, however.)

Artesian water is a fancy name for well water. Brands like Fiji Water pull their product from underground lakes, using massive man-made wells. An underground lake has the ability to regenerate, but excessive pumping can overwhelm its resources—pulling water out of the ground faster than fresh groundwater can seep in, an eco no-no. (The Fiji islands, meanwhile, have a crumbling infrastructure and often undrinkable tap water—though the water brand says it is doing its part to help and doesn’t overpump.)

CSI: H₂O

Curious about the look, smell or taste of your tap water? Our experts explain it all.

“It comes out cloudy at first, then clears up.”

It’s nothing but bubbles. “Sometimes air gets into the pumps that move water through your pipes,” Wunsch explains. “When air dissolves in water, it makes it cloudy. And then, as the oxygen is released, the water clears up.”

“It looks coppery brown.”

“Decaying plants in source water sometimes leach their color, like a steeping tea bag,” explains James M. Symons, Sc.D., professor emeritus of civil engineering at the University of Houston and author of Plain Talk About Drinking Water. Or it could be iron. “It’s colorless in groundwater, but when it combines with air, the iron turns reddish brown,” Symons says. If you see this, consider buying an iron-removal unit. The metal is nontoxic, but it can change the taste of your tap water.

“It smells like rotten eggs.”

The prime suspect here is (harmless) hydrogen sulfide, explains geologist Brian Oram, laboratory director of the Environmental Quality Center at Wilkes University in Wilkes-Barre, Pennsylvania. This stinky gas emanates when bacteria break down naturally occurring sulfur compounds in water. A carbon filter may cure the smell, but occasionally the stink can indicate harmful bacteria lurking in your pipes, so have a pro check it out.

When algae bloom in the rivers and lakes that provide our tap water, the earthy, musty smell can be off-putting, Symons says. Try a carbon filter and alert your water company: Most algae are nontoxic, but the utility can treat the water to attack out-of-control growth. Case closed!